[News Figures] Joseon Astronomer ‘Nambyungcheol’... The First Korean Name Engraved on the Moon

IAU Grants First Korean Name
Top Late Joseon Astronomer
Restoration of Nam Byeong-cheol's Armillary Sphere After 170 Years

For the first time, a crater on the far side of the Moon without a name has been given a Korean name. The protagonist is Nam Byeong-Cheol, an astronomer from the Joseon Dynasty.

On the 19th, Professor Jin Ho's research team from Kyung Hee University's Department of Space Exploration announced that the name "Nam Byeong-Cheol Crater" passed the final review by the International Astronomical Union (IAU) on the 14th. With this, the number of named craters has increased to 1,659. Previously, during international collaborative research, the team discovered a nameless crater on the far side of the Moon exhibiting a peculiar magnetic field and applied to the IAU to name it after Nam Byeong-Cheol.

Nambyungcheol Collision Zone
[Photo by Kyung Hee University]

Nam Byeong-Cheol was a civil official, astronomer, and mathematician in the late Joseon period. His clan origin is Uiryeong. He was born in 1817 (the 17th year of King Sunjo) in Anguk-dong, Seoul, and passed the civil service examination at the age of 21 in 1837 (the 3rd year of King Heonjong). He was appointed to key positions, including Minister of Rites, during the Andong Kim clan's political dominance and was favored by King Cheoljong. In 1859 (the 10th year of King Cheoljong), he concurrently held the positions of Chief Scholar of the Hongmungwan and Director of the Gwansanggam, the government office responsible for astronomy and geography.

His younger brother, Nam Byeong-Gil, who was three years his junior, was also a mathematician and astronomer. The two brothers are regarded as figures who marked the culmination of astronomy in the Joseon era. Their achievements in astronomy and mathematics were made during the 1850s to 1860s, a period when the detrimental effects of factional politics peaked. There is still a lack of detailed research on why such high achievements in these two fields occurred during a time when Joseon was perceived to be in decline across political, economic, and cultural sectors.

His works include Chubosokhae (推步續解), Uigijipseol (儀器輯說), and Haegyeongsechohae (海鏡細草解). The astronomical book Chubosokhae, compiled in 1862 (the 13th year of King Cheoljong), is evaluated as demonstrating the highest level of astronomical understanding reached by a Confucian scholar in mid-19th century Joseon. Applying Kepler's elliptical orbit theory, the book explains calculation methods for five items: the movements of the Sun and Moon, lunar and solar eclipses, and stellar motion. Chubosokhae is an important resource for studying late Joseon astronomy in Korea.

Written in 1859 (the 10th year of King Cheoljong), Uigijipseol contains descriptions of the structure and usage of various astronomical instruments. It classifies and explains ten types of astronomical instruments, including the armillary sphere (혼천의, Honcheonui) and the simplified armillary sphere (간평의, Ganpyeongui). It also reveals the structure and principles of mechanical clocks, including the Western-style alarm clock called Heomsiui. Nam Byeong-Cheol expressed his regret about Joseon's clock manufacturing system in this book, stating, “In France alone, there are about 1,000 clockmakers, and the annual production of various mechanical clocks reaches 12,000 units.”

Uigijipseol, Nam Byeongcheol's Honcheonui
[Photo provided by=Encyclopedia of Korean National Culture, Korea Astronomy and Space Science Institute]

In this book, Nam Byeong-Cheol introduced a new method for making the armillary sphere, and the “Nam Byeong-Cheol armillary sphere,” which had been passed down only in literature, was successfully restored earlier this year after about 170 years. In February, the Korea Astronomy and Space Science Institute (KASI) announced the successful creation of a restored model of the “Nam Byeong-Cheol armillary sphere.” This instrument features a function to adjust the altitude of the celestial pole, the observation reference, allowing celestial observations while changing locations. Additionally, it can obtain various information such as altitude, azimuth, ecliptic longitude and latitude, and right ascension and declination, distinguishing it from existing armillary spheres.

Kim Sang-Hyuk, principal researcher at KASI’s Center for Historical Astronomy, who led the restoration, said, “The Nam Byeong-Cheol armillary sphere is the world’s only scientific instrument among traditional armillary spheres equipped with a re-polar ring that allows actual celestial observation.” He added, “By restoring ancient astronomical instruments, we can understand the level of astronomical observation at the time and enhance the reliability of astronomical records, which is highly significant.”

This content was produced with the assistance of AI translation services.